Jill Lawrence, National JournalWhat does a president have to do these days to get his face carved into a mountainside?My colleague and old friend Ron Fournier contends that President Obama needs to tame gun violence, climate change, and the $ 16 trillion national debt to achieve immortality, and &ldquo;pity his legacy&rdquo; if he fails. In the spirit of the Web, and Joan Rivers, can we talk?&nbsp;